Solving kk-means on High-dimensional Big Data

In recent years, there have been major efforts to develop data stream algorithms that process inputs in one pass over the data with little memory requirement. For the $k$-means problem, this has led to the development of several $(1+\varepsilon)$-approximations (under the assumption that $k$ is a constant), but also to the design of algorithms that are extremely fast in practice and compute solutions of high accuracy. However, when not only the length of the stream is high but also the dimensionality of the input points, then current methods reach their limits. We propose two algorithms, piecy and piecy-mr that are based on the recently developed data stream algorithm BICO that can process high dimensional data in one pass and output a solution of high quality. While piecy is suited for high dimensional data with a medium number of points, piecy-mr is meant for high dimensional data that comes in a very long stream. We provide an extensive experimental study to evaluate piecy and piecy-mr that shows the strength of the new algorithms.Comment: 23 pages, 9 figures, published at the 14th International Symposium on Experimental Algorithms - SEA 201

The directional p-median problem: Definition, complexity, and algorithms

An instance of a p-median problem gives n demand points. The objective is to locate p supply points in order to minimize the total distance of the demand points to their nearest supply point. p-Median is polynomially solvable in one dimension but NP-hard in two or more dimensions, when either the Euclidean or the rectilinear distance measure is used. In this paper, we treat the p-median problem under a new distance measure, the directional rectilinear distance, which requires the assigned supply point for a given demand point to lie above and to the right of it. In a previous work, we showed that the directional p-median problem is polynomially solvable in one dimension; we give here an improved solution through reformulating the problem as a special case of the constrained shortest path problem. We have previously proven that the problem is NP-complete in two or more dimensions; we present here an efficient heuristic to solve it. Compared to the robust Teitz and Bart heuristic, our heuristic enjoys substantial speedup while sacrificing little in terms of solution quality, making it an ideal choice for real-world applications with thousands of demand points

Extracellular HtrA2 Induces Apoptosis in Human Umbilical Vein Endothelial Cells

The serine protease high-temperature-required protein A2 (HtrA2) has been identified as a key intracellular molecule promoting apoptosis in cells during ischemia reperfusion (IR) injury. IR injury in ST-segment elevation myocardial infarction (STEMI) contributes to overall myocardial damage. HtrA2 has further been shown to be significantly increased in the serum of patients with STEMI. In the present pilot study, we use human umbilical vein endothelial cells (HUVECs) to investigate whether extracellular HtrA2 induces apoptosis using Annexin V staining. Furthermore, we examine whether HtrA2 is released extracellularly after staurosporine-induced apoptosis using ELISA. We find that HtrA2 is released upon induction of apoptosis by staurosporine into the cell culture medium. Furthermore, treatment of HUVECs with extracellular HtrA2-induces apoptosis, while the addition of anti-HtrA2 antibodies reduces both HtrA2- and staurosporine-induced endothelial cell apoptosis. In conclusion, we show here that extracellular HtrA2 induces apoptosis in human endothelial cells, although the exact molecular mechanisms have to be investigated in future

Design of a 20 MWth Carbonate Looping Pilot Plant for CO2-capture of Coal Fired Power Plants by Means of Limestone

The feasibility of the post combustion process Carbonate Looping has been confirmed through operation of various test rigs at different scales worldwide. This work describes the development of a 1 MWth test rig to a 20 MWth pilot plant, shows some important and essential test results of the 1 MWth plant and presents a basic design study with a final setup of the 20 MWth pilot. The erection and operation of a pilot plant in a scale of 20 MWth is considered as a further milestone with regard to a large scale application of this technology

Welches Verständnis von Ökonomie haben Medizinstudierende?

Introduction: Economic topics appear in the medical studies curriculum at different times. Despite socio-political relevance, there is hardly any information about the degree of understanding that medical students have of "economics in medicine". The present study addresses the questions: What understanding of "economics in medicine" do medical students have before the start of the Practical Year? To what extent is economic teaching content understood as "economization" from outside the profession?Method: Magdeburg medical students in the 5th year of study, who participated in preparatory seminars for the Practical Year (PY) in 2014 and 2015 (60 participants each), assessed the relevance of various seminar topics four months prior to the start of the semester. On the basis of a three-stage qualitative-reconstructive partial evaluation, students' economic understanding is explored through secondary analysis: deductive derivation of the analysis units; integrative basic method ("segmentation", "micro-linguistic detailed analysis", "central theme"); development of a theoretical model by placing the central themes in context following Grounded Theory. Results: Based on the theory, 19 free-text answers with economic reference were identified from the total of all free-text answers. Each answer was assigned to at least one of a total of six themes of the students' understanding of economics: de-professionalizing economization, deciding and working economically, ambivalent requirements for efficiency and equity, the doctor as an entrepreneur, economics as relevant learning content, PY as a conflict-laden setting for economized working and learning. The theoretical model contains social, praxeological and professional references, which can themselves be ambivalent and conflicting.Conclusion: Despite their critical attitude, the surveyed medical students are neither hostile to economics nor do they regard economics in medicine as a taboo subject. Economic learning content is recognized as relevant. Educational formats that tackle the tension between patient and system orientation in a problem-oriented manner can be a productive setting for economic reflection.Einleitung: Ökonomische Themen sind im Medizinstudium zu verschiedenen Zeitpunkten curricular verankert. Trotz gesellschaftspolitischer Relevanz bestehen kaum Kenntnisse darüber, welches Verständnis Medizinstudierende von 'Ökonomie in der Medizin' haben. Die vorliegende Untersuchung geht den Fragen nach: Welches Verständnis von 'Ökonomie in der Medizin' haben Medizinstudierende vor dem Beginn des Praktischen Jahres? Inwiefern werden ökonomische Lerninhalte als professionsfremde "Ökonomisierung" verstanden?Methode: Magdeburger Medizinstudierende im 5. Studienjahr, die 2014 und 2015 an Vorbereitungsseminaren für das Praktische Jahr (PJ) teilnahmen (je 60 Teilnehmende), schätzten vier Monate vor Seminarbeginn teilstandardisiert-fragebogengestützt die Relevanz verschiedener Seminarinhalte ein. Anhand einer dreistufigen qualitativ-rekonstruktiven Teilauswertung werden studentische Ökonomieverständnisse sekundäranalytisch exploriert: Deduktive Ableitung der Analyseeinheiten; Integratives Basisverfahren ("Segmentierung", "mikrosprachliche Feinanalyse", "zentrales Motiv"); Inbezugsetzung der zentralen Motive als theoretisches Modell nach Grounded Theory. Ergebnisse: 19 Freitextantworten mit ökonomischem Bezug wurden theoriegeleitet aus dem Gesamt aller Freitextantworten identifiziert. Jeder Antwort wurde mindestens eine von insgesamt sechs Motiven studentischen Ökonomieverständnisses zugeordnet: De-professionalisierende Ökonomisierung, Wirtschaftlich entscheiden und arbeiten, Ambivalente Effizienz- und Gerechtigkeitsanforderungen, ÄrztIn als UnternehmerIn, Ökonomie als relevanter Lerninhalt, PJ als konflikthaftes ökonomisiertes Arbeits- und Lernsetting. Das theoretische Modell beinhaltet gesellschaftliche, praxeologische und professionelle Bezüge, die in sich ambivalent und zueinander konflikthaft sein können.Schlussfolgerung: Die befragten Medizinstudierenden sind trotz kritischer Haltung weder pauschal ökonomiefeindlich noch tabuisieren sie Ökonomie in der Medizin. Ökonomische Lerninhalte sind als relevant anerkannt. Lehrformate, die problemorientiert das Spannungsfeld zwischen Patienten- und Systemorientierung aufgreifen, können ein produktives Setting für ökonomische Reflexion sein

Safety and tolerability of the antimicrobial peptide human lactoferrin 1-11 (hLF1-11).

Contains fulltext : 81619.pdf (publisher's version ) (Open Access)BACKGROUND: The treatment of patients with haematological malignancies by means of haematopoietic stem cell transplantation (HSCT) is often accompanied by life threatening infections. With emerging antimicrobial resistance there is an increased need for new agents, with a beneficial safety profile. Therefore we evaluated the safety of the promising new antimicrobial peptide human lactoferrrin 1-11 (hLF1-11) in healthy volunteers and patients. METHODS: We undertook a sequential, randomised, double-blind, placebo-controlled study using ascending single (0.005, 0.05, 0.5, 5 mg) and multiple intravenous doses (0.5, 5 mg) in healthy volunteers, and open-label, single intravenous 5 mg doses in autologous HSCT recipients. Results : Single and multiple doses of hLF1-11 were tolerable up to 5 mg intravenously in healthy volunteers, while 5 mg single dose was tolerable in patients. Elevations in transaminases possibly related to treatment were reversible and not serious. CONCLUSION: The new antimicrobial hLF1-11 is well tolerated in healthy volunteers with repeated daily doses up to 5 mg. The side-effect profile is very favourable for an antimicrobial, the only undesirable effect being a possible elevation of transaminases, which may be related to hLF1-11 although the current data do not allow conclusive interpretation of treatment relationship. A lower dose is recommended for the forthcoming multiple dosing studies in HSCT patients. TRIAL REGISTRATION: ClinicalTrials.gov: nct00509938

What You See is What You Store: Database-Driven Interfaces

Any graphical user interface (GUI) requires large amounts of complex metadata for the layout of windows and menus, their style and behavior, their bindings, etc. Designing, debugging and maintaining this interfaces is a difficult task and objectorientation is of little help as it tends to overcrowd the code with these metadata. Following a similar idea by Goyal et al., who considered GUI programming a database research problem and gave solutions based on logical programming, we propose storing these metadata in a database which we connect to a scripting language, here Tcl. We explain the details first with a small example where the database acts as a front-end to MathematicaÒ. Next we indicate schemes, tables and generic methods for automated GUI design. Finally, we discuss the ultimate step, namely managing the interface at run-time from the database. In concluding, we present arguments for our belief that this technique goes well past current GUI builders and has great potential for ..